Support Area

This is another support request for our new members directory at ela.biz. The software isn't responding to my control panel changes, so I figure there is some kind of script solution for this problem too.
The problem is that any members directory should show people in alphabetical order by last name, starting with the first letter of the alphabet. Any other order system ticks users off.
I've played with the section settings in the control panel, and nothing changes in the front end view.
This is a bit of an unusual case in that our directory uses a database table from the OSE Membership subscription component.
OSE collects "name" in two separate fields: firstname and lastname.
We hired SobiPro - among other things - to run the two fields together into one name in Sobi Pro.
Although the name field published by Sobi Pro combines the two, the lastname field is still there providing half the name data, if you will.
We want to use that lastname field to order the directory list view. Can someone point where I can do this? I am very handy with code. Your system certainly makes sense to me, although I'm not always clear exactly how the files work together.
You can see the directory here: https://newela.biz/member-services/members-pages/members
This a registered access page. I am happy to provide front and back end logins.
Thank you,
-Jim Gribble